Support Forum

I have an old forum that recently broke - I'm getting the following error for all forums:

Warning: Creating default object from empty value in /problem-with-post-edit-buttonome/yourbus/public_html/wp-content/plugins/simple-forum/library/sf-database.php on line 2086

having read the site I recognize I need to upgrade however - I read that I need to be running 4.5+ in order to get to 5.5 and I can't see anywhere how to get from 4.3.5 to 4.5.

If someone could point me in the right direction I'd be very grateful.

Thank you for your help.

(Oh - and apologies for sending a version of this through the contact form - I was hunting for a forum that addressed issues with 4+ and couldn't see anything ;-p )

Andrew